Fabrication of GaAs/GaAlAs transport devices using a deep submicron trench etching technique

This paper demonstrates a submicron trenching technique for defining low‐dimensional electron systems in GaAs/GaAlAs heterostructures for transport measurements. A variety of electron systems can be defined between trenches as narrow as 200 nm etched into a suitable heterostructure. The use of narrow trenches gives the advantages of high resolution, simplicity, and flexibility, and also avoids the complications associated with negative resists and lift‐off techniques. Using the trenching technique, we have fabricated Aharonov–Bohm ring devices with a Schottky gate over the entire ring. At 0.4 K, these devices exhibit clear interference effects which are dependent on the gate bias.